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1/4 scale Citabria don't want to turn

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1/4 scale Citabria don't want to turn

Old 04-03-2012, 03:47 AM
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goirish
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Default 1/4 scale Citabria don't want to turn

I have a Bud Nosen 1/4 scale Citabria 52 gas. Doesn't want to turn unless you use lots of rudder. In fact it will turn better with rudder alone. Any suggestions. I could set up the differential greater than I have it and add more throw.
Old 04-03-2012, 04:26 AM
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mike109
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Default RE: 1/4 scale Citabria don't want to turn

G'day

I have a Black Horse Decathlon (son of Citabria) and it is very similar. They are "close coupled" planes - long wing, short fuse, and this sort of adverse yaw effect is pretty standard for these planes. If I don't use rudder with the Decathlon, it just runs wide in turns with its tail hanging down.

The "quick and dirty" solution is some aileron mixed into rudder but the real solution is to learn to do "coordinated turns" using the rudder in the turn. I am still trying to learn how to do it properly.

Have fun. Oh yes, Telemasters and Cubs do it too to a more or less extents. And so does my Auster.

Mike in Oz

Old 04-03-2012, 04:59 AM
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Default RE: 1/4 scale Citabria don't want to turn

I know I am not real good with the rudder but this takes a lot more than my 1/4 scale cub.
Old 04-03-2012, 05:40 AM
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Default RE: 1/4 scale Citabria don't want to turn

Does it roll with just aileron? It is after all an aerobatic airplane
Old 04-03-2012, 05:48 AM
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Default RE: 1/4 scale Citabria don't want to turn

It just kinda tilts. Sorry I can't tell you exactly what the puppy does. It will turn but you need 3 states to complete it without lots of rudder. I set the mix at 25% aileron/rudder. I also have the ailerons going up about 30% more than down. Will try again when the rain quits. it was built to use as a tug for our gliders.
Old 04-03-2012, 06:16 AM
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Default RE: 1/4 scale Citabria don't want to turn

Yes definately use a rudder to aileron mix especially if you are using the ship for aerotow. And I would use slightly more than what you are using maybe around 30/35%. It is a mistake to not use this mix simply because of machismo.

Remember what turns the airplane is the elevator after the ailerons have established the bank angle and the rudder maintains the proper yaw trim.

Under tow you may find assuming the tow release is above the tugs CG that the the yaw axis becomes much more sensitive especially at low airspeeds and will require much much more concentration even though you may be using a rudder to aileron mix.

Would love to see what you have come up with for the release.

John
Old 04-03-2012, 06:18 AM
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Default RE: 1/4 scale Citabria don't want to turn

Use the vertical with an Immelmann turn to change direction 180 degrees & keep it over the landing zone till you sort it out.
Old 04-03-2012, 06:21 AM
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Default RE: 1/4 scale Citabria don't want to turn

John I will send a picture of the release up close.
Old 04-03-2012, 07:09 AM
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Default RE: 1/4 scale Citabria don't want to turn

Don't use a mix...not for a turn...learn the rudder...you'll be a better pilot for it
Old 04-03-2012, 07:24 PM
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jester_s1
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Default RE: 1/4 scale Citabria don't want to turn

Yeah, I don't get the point of mixing rudder in either. It's not that hard to push a little rudder while pushing some aileron. A mix can get you into trouble too at lower speeds when you need to correct for a little turbulence in the roll position but your alignment with the runway is good.
Old 04-04-2012, 10:41 AM
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Default RE: 1/4 scale Citabria don't want to turn

What are your throw settings on Elev, Aileron and Rudder ????? ENJOY !!! RED
Old 04-04-2012, 11:12 AM
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Default RE: 1/4 scale Citabria don't want to turn

Gene, on some of the high wing stunt planes like the Decathalon and Citabria require a lot of Aileron Differential. In your case it sounds like you need a bunch. More Up then Down. Adding a bit of ruder mix isn't a bad thing, I have a 68 inch bipe that had a little Yaw problem. {Nothing like yours} I mixed in about 10% rudder and had it on a switch. That was when I was first flying the plane at IMAA events. 10% isn't much and I almost never bothered with it, just used rudder by hand. I am a rudder user but I wanted to try the mix. Using as mush rudder as you are is not exceptable, try changing the aileron throws and adding a bunch of Diff. I use a bit of Diff in most of my planes, even stunt planes but it's the slow high winged planes that require it the most. If a photo shows up here I'm testing my photo file that didn't load last time I tried. No big deal or mystery!!
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Old 04-04-2012, 05:11 PM
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Default RE: 1/4 scale Citabria don't want to turn

What is that, one of them old cheap YS's
Old 04-04-2012, 05:36 PM
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Default RE: 1/4 scale Citabria don't want to turn

I have seen a lot of old YS engines but never a cheap one!! That is one of the first pumpers OS came out with. In this case it is a 1.20 Surpass. That isn't exactly the truth about YS either. Last summer I did pick up an almost new 1.10YS for a hundred bucks. It had a repair on it done by Clarence Lee and all we can figure is the original owner fired up the engine, flew the plane and the header came loose or he stripped it out when installing?? Then he crashed the plane. Engine had a broken prop on it with crash dirt still clinging to it.
I installed the engine on a test plane and it fired right up, was in tune on the low end and blew out the new engine gray snot for the first few flights, about 5 flights then it cleared up. See, a deal can be found once in a while. In the case of this OS 1.20, I can really make you a deal!!!!!!!!!!!!!!!!!!!!!!!!!! Trust me!!![:-]
Old 04-04-2012, 07:29 PM
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jester_s1
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Default RE: 1/4 scale Citabria don't want to turn

The only negative about differential is that inverted everything is backwards. The plane probably still needs some even if you are flying aerobatics with it, but just understand that getting it perfect upright may cause yawing in a slow roll.
Old 04-04-2012, 08:34 PM
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Default RE: 1/4 scale Citabria don't want to turn

Its a glider tug not an aerobat, It should be set up to be as comfortable and forgiving as possible If its going to fulfill its mission for any length of time.

Differential to minimise adverse yaw, Oh you bet. No pushing the CG to the rear as in some aerobatics and a mild rudder to aileron mix absolutely.

These are three of the items are tantamount for a successful Tug.

Thank you Goirish I would love to see the pics of your tug release. Its always great to see what others have come up with. Mine is an old controlline stooge I made a long time ago and converted by adding a servo to trip it instead of a trip line.

John
Old 04-05-2012, 12:24 AM
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Default RE: 1/4 scale Citabria don't want to turn

G'day again

I just looked at how my Decathlon is set up. I am using 100% aileron into rudder mixing. I generally fly it on low rates which are set at aileron 70% with 30 % exponential and similar elevator setup. Flown like this, it flies like a trainer so long as it is kept upright.

With the mix off and high rates, it rolls quite well but it just won't turn without rudder. When I have forgotten to turn the mix off and tried to roll, it is rather messy as it noses down as it rolls initially but it gets round in a sort of barrel roll. Not pretty though.

It is easy to land with the mix on but nearly impossible with it off as as it slows down, the ailerons become less effective and it just wanders off to the right unless corrected with rudder.

I also had a quarter scale Cub (Hanger 9). It was much easier to fly and did not need rudder to get it to turn though I had a switched mix set up at about 25%.

It is also not that easy to take off. The trick is to get the tail up with gentle power then gently increase the power while keeping it straight and eventually it floats off. Too much power and it will rear up, stall and snap to the left quite violently. Gentle power is the trick. It is a 60 size model with a Laser 100 four stroke engine.

The mix also makes it easier to fly slowly. Without the mix it tends to wander.

Despite all this, it is good to fly and gets admiring comments - particularly about the very quiet engine.

Cheers

Mike in Oz
Old 04-05-2012, 02:49 AM
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goirish
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Default RE: 1/4 scale Citabria don't want to turn

John, I am taking a picture of it today and will post it. It is a tug, I have other planes for aerobatics. Just want to pull and release. Will try it with the new settings Friday or Saturday and post results.
Old 04-05-2012, 03:18 AM
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goirish
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Default RE: 1/4 scale Citabria don't want to turn

John, still going to take a picture but if you go to RCaerotowing.com then click on articles. Scroll down to building a easy and simple tow plane release. This is the 2nd tug with this set-up. the other tug is a Hobby Lobby senior telemaster. this will show a step by step construction of the tow release. Actually this is a good site. They will be presenting again at the Weak Signal's show in Toledo on 4/ 13,14 and 15. I will attend the symposium again this year.

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